Advances in technology have enabled manufacturers to miniaturize sensing components. As a result, these miniature sensing components are being embedded into many devices that previously could not house such components. Examples include wireless telephones being embedded with miniature cameras and personal digital assistants (PDAs) being embedded with miniature sound recorders.
One problem resulting from this miniaturization technology is that the physical presence of these sensing components is very difficult to detect. Even if certain devices are themselves noticeable, their miniaturized sensing components are not. As a result, devices embedded with these miniaturized sensing components are being used to record and disseminate unauthorized images and sounds (media) without the knowledge or consent of the media owners. Wireless telephones embedded with miniature cameras, for example, are used to record and transmit unauthorized images and sounds.
The present invention proposes the use of watermarking as a means for securing and regulating sensing devices and sensed media. Similar to its paper origins, watermarking in the present context is a technique for altering images or sounds so as to embed security information into them for the purposes of authenticating, tracing, and securing the recorded media. The information may be hidden or not depending on the specifics of the application. A current method for watermarking image and/or audio data (media) includes manipulating the sensed media after it has been recorded. Such watermarks are added, for example, via the recording device itself or via computer manipulation of the recorded media. This common form of watermarking is illustrated in FIG. 1A.
A sound or image (media) 102 is recorded by a recording device 104. Once the media is recorded, the recording device 104 manipulates the recorded media 102 thereby embedding a watermark into the media. After the watermark is added 105, the watermark-embedded media is stored 106 or transmitted 108.
Implementing the above described watermarking technique requires some degree of cooperation from a recording device or from its user. In other words, the recording device must be provided with additional hardware, firmware, or software which automatically embeds watermark information into recorded media or the user must voluntarily choose to embed a watermark in recorded media. It is doubtful, however, whether it is possible to universally implement such a system in which recording devices or their users are cooperative in the watermarking of unauthorized recordings. Even if such cooperation were mandated by law, the production of sensing devices that do not contain a cooperative function can still occur. Further, there are ways to defeat such safeguards even if they are included in the production of sensing devices.
An alternate method for watermarking recorded media includes embedding a watermark in the media itself prior to its being recorded. As shown in FIG. 1B, prior to being recorded by a recording device 107, a watermark 109 is embedded into sound and/or image media 103. Once recorded, the recording device 107 stores 110 or transmits 112 the watermarked media. Although no cooperation is required, embedding a watermark into the media itself tends to disturb the media's integrity.
Accordingly, it is desirable to have a method and apparatus for forcing a recording device to record a watermark along with protected media without requiring the cooperation of a recording device or its user and without having to embed the watermark into the protected media itself.
It is also noted that there does not exist an effective method or apparatus for identifying and/or locating an unauthorized recording device and/or their users engaged in the unauthorized recording of protected media. The lack of such technology is of particular concern when sensing devices are hidden and remotely activated. Without locating offending persons and/or devices, unauthorized recordings are not easily regulated, even if it is known that recording is occurring.
Accordingly, it is desirable to have a method and apparatus for identifying and locating unauthorized recording devices and/or their users engaged in the unauthorized recording of protected media.